CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 24, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 92,862	$ 56,672
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	39,893	24,516
Stock-based compensation expense	10,911	7,750
Amortization of convertible notes debt discount	4,495	0
Deferred income taxes	(1,088)	(3,748)
Other non-cash items	(2,739)	499
Change in operating assets and liabilities, net of acquisitions of businesses:
Trade receivables	(29,295)	(57,346)
Inventories	(13,238)	(20,093)
Prepaid expenses and other assets	4,299	(2,240)
Accounts payable, accrued liabilities and other	21,313	26,857
Net cash provided by operating activities	127,413	32,867
CASH FLOWS FROM INVESTING ACTIVITIES
Capital expenditures	(26,073)	(13,238)
Business acquisitions	(290,052)	(97,261)
Other investing activities	5,125	170
Net cash used in investing activities	(311,000)	(110,329)
CASH FLOWS FROM FINANCING ACTIVITIES
Term debt borrowings	36,981	0
Term debt repayments	(6,441)	(7,883)
Borrowings on revolver	954,535	353,442
Repayments on revolver	(877,931)	(358,365)
Stock repurchases under buyback program	(75,028)	0
Proceeds from convertible notes offering	172,500	0
Purchase of convertible notes hedges	(31,481)	0
Proceeds from sale of warrants	18,147	0
Payments related to vesting of stock-based awards, net of shares tendered for taxes	(2,659)	(3,042)
Proceeds from public offering of common stock, net of expenses	0	93,306
Proceeds from exercise of stock options	3	926
Payment of deferred financing/debt issuance costs	(7,485)	(995)
Other financing activities	(15)	(5)
Net cash provided by financing activities	181,126	77,384
Decrease in cash and cash equivalents	(2,461)	(78)
Cash and cash equivalents at beginning of year	2,767	6,449
Cash and cash equivalents at end of period	$ 306	$ 6,371